I have a half dozen Etro shirts and I don't know if any of them have serial numbers because I haven't looked. I am certain of their authenticity, and likewise members have assured you the shirt you posted is authentic as well. Screw the number, it's real, what more do you want? Do you expect someone to be able to tell you, "Oh, I saw that exact pattern at the SS08 sample sale, I recall it precisely, it was sold for $59.99 at 253 Avenue Mouton from 1pm to 3pm on March 8th, the serial number tag was removed on checkout to prevent returns to a B&M store"??? That's not going to happen. If there is no satisfactory answer, just return it. No matter how you slice it, this entire topic is ridiculous.